Apparatus for electrical treatment of fluids



- Oct. 30, 1934. Q H

APPARATUS FOR ELECTRICAL TREATMENT OF FLUIDS Filed July 30, 1932 INVENIOR CARL HAHN BY MW fl/M ;7--4

A fro/e NE Y5 Patented Oct. 30 1934 APPARATUS FOR ELECTRICAL TREATMENTOF FLUIDS Carl Hahn, Berlin-Siemensstadt, Germany, as-

signor to International Precipitation Company, Los Angeles, Calif., acorporation of California Application July 30, 1932, Serial No. 626,926In Germany August 8, 1931 6 Claims.

This invention relates to the electrical treatment of gases or liquids,for the purpose of removing suspended particles therefrom or for otherpurposes.

The invention is particularly applicable for use in electricalprecipitation of suspended particles from gases, or in the electricaltreatment of petroleum emulsions or other liquid emulsions for thepurpose of separating the emulsified constituents. However, it may beutilized in any process in which a fluid is subjected to the action of ahigh potential electric discharge between opposing electrode means.

It has already been proposed in United States patent applications,Serial Nos. 527,690 and 613,- 783, to improve the efliciency ofapparatus of this type by applying to the opposing electrode means ofsuch apparatus, impulse potentials of extremely short durationand'extremely steep wave front, while providing intervals of relativelylong duration between successive impulses. The utilization of potentialimpulses of this type provides for copious production of ions, at theinstant of each impulse, to effect charging of the suspended particlesor other desired result, and also serves, in the case of electricalprecipitating or separating processes, to maintain the necessaryeffective potential between the electrodes to cause migration of thecharged particles toward the electrode surfaces and precipitation ofsuch particles thereon, while at the same time substantially preventingarcing or disruptive discharge between the electrodes, owing to the factthat before the resistance of the fluid between the electrodes issufficiently reduced, by ionization or other phenomenon incident to theimpulse discharge, to permit arcing or disruptive discharge, the impulseenergy is substantially dissipated and the inter-electrode potential hasdecreased to such a low value as to prevent the formation of an arc,disruptive discharge or short circuit between the electrodes.

Said patent applications have also disclosed suit-.

able apparatus for producing potential impulses of the type abovedescribed, such apparatus comprising in general, capacity meansconnected to the source of electric power supply and a spark gap orsimilar device connected between said capacity means and the electrodesof the fluid treating apparatus, said spark gap being adapted to breakdown when the capacity means becomes charged to a certain potential, andthus discharge the energy stored in said capacity means to saidelectrode means and suddenly apply a high potential across saidelectrode means, which potential thereafter decreases rapidly due to thedischarge of said condenser and the extinguishing of the spark acrosssaid gap.

Also, in patent application Serial No. 578,830, it is proposed toconnect a plurality of sections or parts of an electrical fluid treatinginstallation to a common source of potential impulses of the type abovedescribed, and to provide means for successively and separatelyconnecting the respective sections or parts of such installation to saidpotential impulse source.

A principal object of the present invention is to provide an apparatusin which the above-described advantages are obtained at a minimum costof installation and operation, and with increased efficiency.

A further object of the invention is to provide advantageous means forsupplying intermittent high potential impulses of extremely shortduration to a plurality of electrical treating units or a plurality ofsections or portions of an electrical p treating apparatus, in which theelectrical energy for all of said units, sections or portions, isobtained from a common source of high potential unidirectional current.

According to this invention, the electrical circuit connecting thecommon source of high potential unidirectional current to the electricaltreating apparatus comprises a plurality of branch circuits leading fromsaid source to the several units,

sections or portions of such apparatus, and a sep- 0 arate impulseproducing means, such as a condenser and spark gap, connected to each ofsaid branch circuits. Furthermore, means are preferably provided forcontrolling the operation of the respective impulse producing means soas to cause the potential impulses to be delivered to the respectiveunits, sections or portions at difierent times.

The accompanying drawing illustrates apparatus in accordance with thisinvention and referring thereto:

Fig. 1 is a diagrammatic representation of one form of such apparatus'Fig. 2 is a similar view of another form of apparatus.

Fig. 3 is a. similar view of another form of apparatus.

In Fig. l, S indicates, in general, a source of high potentialunidirectional electric current, one side of which is grounded asindicated at land the other side of which is connected through supplyline 2 and through branch circuit connec tions 2a, 2b and 20 to aplurality of electrical treating units A, B and' C. Said electricaltreating units may consist of any devices adapted to subject a fluid tothe action of a high potential electrical discharge for the purpose ofseparating suspended particles therefrom or for other purpose, such aselectrical precipitators, electrical emulsion-breaking devices etc. Saidunits may also consist of different portions or sections of anelectrical treating apparatus.

The supply source S is shown as comprising a transformer 11 for steppingup the supply volt age to the desired value, and rectifying means 12connected to the secondary winding of said transformer. Said rectifyingmeans may, for example, comprise two thermionic rectifiers, Whosefilaments are energized through suitable transformers 14 and 15. Therespective rectifiers are connected by Wires 16 and 17 to the oppositeterminals of said transformer secondary winding, while the mid-point ofsaid winding is grounded at l. The output terminals of said rectifiersare connected by wires 18 and 19 to the supply line 2. Said rectifiersare so connected as to permit electric current to pass from thetransformer to the supply line 2 in one direction only. For example,when used in connection with elecl ical precipitation apparatus, saidrectifiers ar'- preferably so connected as to permit passage of electriccurrent from each transformer terminal during only the alternate halfwaves when said terminal is at negative potential with respect toground. a

Each of the electrical preeipitators or other treating units A, B and Cis shown as comprising a high tension electrode 35, an opposingelectrode member 36 electrically grounded at 37, and inlet and outletconnections 38 and 39 by means of which the fluid to be treated may bepassed between said electrodes 35 and 36. Suitable insulation 41 isprovided between electrode members 35 and 36.

Rotary spark gap devices 3a, 3b and 3c are connected between the branchconductors 2a, 2b and 2c and the corresponding treating units. Each ofsaid spark gap devices is shown as provided with four insulating arms22, mounted on a rotating shaft 23 driven at any suitable speed, andeach of said arms is provided at its extremity with an electrode element24, preferably of spherical or rounded shape. Said electrode elementsare connected in two diametrically opposed pairs by means of conductors25 and 26. Diametrically opposite to one another with respect to saidspark gap devices and in sparking relation with respect to the elctrodeelements 24, are provided fixed electrode elements 27 and 28, the formerbeing connected to the corresponding branch conductors 2a, 2b and 2c,and the latter being connected by conductors 4a, 4b and 40 to the hightension electrode element 35 of the corresponding electrical treatingunit. At a point approximately midway between the electrode elements 27and 28 there is provided another electrode 29 connected by wire 31 to animpulse condenser or capacity means 50., 5b or 50, the other side ofwhich is grounded as indicated at 33.

The contact members 24 of each rotary spark gap device are preferablyoff-set angularly with respect to those of the other devices, so as tocause said devices to operate at different times, as hereinafterdescribed. In the particular construction shown, said contact members inthe respective spark gap devices are set at an angle of 60 with respectto one another, so that said devices will operate successively at equalintervals.

A charging condenser 42 is preferably connected to the power supplycircuit between the source S and the rotary spark gap devices abovedescribed, one side of said condenser being connected to the main supplyline 2 and the other side thereof being grounded as indicated at 43. Aresistance or inductance 34 is preferably provided in line 2 betweencondenser 42 and the rotary spark gap devices, and another resistance orinductance 44 may be inserted between rectifier means 12 and condenser42.

In the operation of the above-described apparatus, a unidirectionalhigh'potential is supplied by source S to the supply line 2. When therotary spark gap devices are in the position shown, with the electrodeelements 27 and 29 of device 3a in sparking relation with respect to oneof the diametrically opposed pairs of electrode elements 24, thecorresponding impulse condenser 5a is charged by energy received fromthe supply source S and also from the charging condenser 42. As thisspark gap device 3a passes somewhat beyond this position the spark isextinguished at the gaps between electrode elements 27-24 and 2425, andwhen the commutator has rotated through 90 the other pair of electrodeelements 1:; is brought into position of sparking relation with thefixed electrodes 28 and 29. The impulse condenser So then dischargesthrough conductor 4a to the high tension electrode member 35 of thetreating unit A, causing a high potential impulse of extremely steepwave front and short duration to be applied between said electrode 35and the opposing electrode 36.

This results in a uniform and intense electrical discharge from the hightension electrode. For example, in the case of electrical precipitationapparatus, an intense negative corona is thus produced over the entiresurface of the electrode 35, and the ions thus produced cause suspendedparticles contained in the gas to become electrically charged and to beprecipitated toward the opposing electrode 36. However, before anydisruptive discharge or arcing can occur, the electrode elements 24 ofthe spark gap device pass out of sparking relation with the fixedelectrodes 28 and 29, so that the supply of electrical energy to theelectrodes of the treating unit ceases and the potential between saidelectrodes falls below the discharge potential.

It will be evident that each impulse condenser, such as 5a, issuccessively charged from the supply line 2 and discharged through thecorresponding electrical treating unit. such as A, twice during eachrevolution of the corresponding spark gap device, such as 3a, and thatsaid impulse condenser and electrical treating unit are entirelydisconnected from the power supply source during the time of dischargeof such condenser, so that the sharp potential impulse created upon suchdischarge is prevented from reaching the power supply means.

The operations of the respective spark gap devices 3a, 3b and 3c, followone another at intervals of 60 in the rotation thereof, so that energyis delivered from the supply source S and charging condenser 42, throughline 2, successively to the respective impulse condensers 5a, 5b and 5c,and the energy thus stored in said impulse condensers is successivelydischarged through the corresponding treating units A, B and C.

The charging condenser 42 serves to store electrical energy from thesource S during the short time intervals when none of the impulsecondensers 5a etc. are in connection with the supply line 2 and todischarge this energy to said impulse condensers when they are' soconnected.

The resistances or impedances 34 and 44 serve to prevent high frequencytransients during the charging of any one of the impulse condensers 5aetc., and to prevent any oscillations which may occur in this part ofthe circuit from reaching the power supply source S.

It will thus be seen that the conductors 2a and 4a, 2b and 4b, and 2cand 4c define a plurality of branch circuits leading from the commonsource S to the respective treating units A, B and C. In each of thesebranch circuits, means are connected for creating sharp unidirectionalpotential impulses of extremely short duration and delivering suchimpulses to the respective treating units, such means comprising therespective impulse condensers and spark gaps, such as 5a and 3a. Theseimpulses are substantially confined, in each case, to a local,

impulse circuit including the condenser, spark gap, and treating unit,and high frequency oscillations or transients are substantiallysuppressed in all other parts of the circuit by the resistances orinductances 34 and 44. Furthermore, the operations of the respectiveimpulse producing means are so controlled as to cause the impulses tooccur at different times in the respective impulse circuits, thiscontrol being accomplished by the angular offsetting of the electrodesof the respective rotary spark gap devices.

In the apparatus shown in Fig. 2, the rectifying means 12' oi. the powersupply source S is shown as a mechanical rectifier, comprising a disc 46of insulating material adapted to be rotated in synchronism with thealternating current supplied to transformer 11, opposing contactsegments 47 mounted on said disc, two diametrically opposed fixedcontact segments 48 and 49 connected to the respective terminals of thesecondary winding of said transformer, and two additional diametricallyopposed fixed contact segments 51 and 52 disposed between the segments48'and 49. The contact segment 51 is electrically grounded at 1, whilethe segment 52 is connected to supply line 2. The rotation of disc 46and contact segments 47 serves to reverse the connections between theassociated fixed contacts at each half cycle of the alternating currentsupplied to transformer 11', and thus maintain a unidirectional highpotential between supply line 2 and ground.

Charging condenser 42' is connected as before, between said supply line2 and a ground connection 43. A rotary distributing switch 54 serves tosuccessively connect supply line 2' to the respective branch conductors2a, 2b, and 2c.

Said distributing switch is shown as compris ing a rotating contact arm55, adapted to be rotated at any suitable speed and provided with acontact member 56 making contact successively with contact segments 57a,57b and 570.

The several branch conductors 2a, 2b and 2c are connected to oneelectrode of the corresponding spark gaps 3a, 3b and 30, while the otherside of said gaps is connected to the high tension electrode member 35'of the corresponding treating units A, B and C. Each of said treatingunits is provided, as before, with opposing electrode means 36, which iselectrically grounded at 37. Each of said branch conductors is alsoconnected to an impulse condenser 5a, 51) or 50, the other side of whichis electrically grounded at 33.

Resistances or inductances 34' and 44' may also be provided, either inthe positions shown in Fig. 2 or in the same positions as shown in Fig.1, for suppressing high frequency oscillations in all parts of thecircuit outside of the impulse circuits of the respective treatingunits, said impulse circuits including the respective impulsecondensers, spark gaps and treating units, such as 5a, 3a and A.

In the operation of this form of apparatus, the supply line 2 ismaintained, as before, at a unidirectional high potential with respectto ground, by operation of rectifier l2, and chargingcondenser 42 isalso kept charged at substantially this potential. The distributingswitch 54 causes the supply line 2' to be successively connected to therespective impulse condensers 5a, 5b and 50. When any one of thesecondensers, such as 5a, is so connected, it is charged until the voltageacross the corresponding spark gap such as 3a becomes sufiicient tocause a break-down of said gap, whereupon said condenser dischargesthrough said spark gap and the corresponding treating unit such as A.The dimensions of the spark gaps and 'impulse potentials may be soproportioned with respect to the size of the treater units and thecharacteristics of the power supply, as to cause any desired frequencyof repetition of the impulses thus delivered to the treater unit. Thus,each of the spark gaps, such as 3a, may be caused to break down once orany desired number of times during each period when said gapis-connected to the power supply source through switch 54. Furthermore,the total period during which said switch establishes connection to eachspark gap and its associated impulse condenser may be determined byregulating the speed of rotation of contact arm 55. Also, the circuitmay be so adjusted as to cause breakdown of one or the other of theseveral spark gaps to occur once or more than once during each rectifiedhalf-wave voltage impulse delivered by the rectifier 12, or at aninterval greater than the period of each such half-wave impulse, inwhich case several of such half-wave voltage impulses are required tocharge each impulse condenser, such as 5a, to a sufficient voltage tocause such break-down of the associated spark gap, such as 3a.

Fig. 3 illustrates still another modification of the invention. In thiscase, the supply line 2" is again charged at unidirectional highpotential by means of transformer 11" and rectifier 12 The rectifier isshown as comprising a single thermionic rectifier connected between oneterminal of the secondary winding of transformer 11" and the supply line2", while the other terminal of said transformer winding is grounded asindicated at 1". However, it will be understood that either of the abovedescribed forms of rectifying means mayalso be used in connection withthis form of the invention. Branch conductors 2a, 2b and 20 lead fromthe supply line 2" to the respective spark gaps 3a", 3b" and 30", whilethe other side of said gaps is connected to the corresponding treatingunits A", B and C. Impulse condensers 5a, 5b and 5c" are also connectedto the respective branch conductors 241-" etc., and are connected at theother side to ground, as indicated at 33". A resistance or inductance34" is also provided in each of said branch conductors, at a point inadvance of the connection of the impulse condenser thereto, so as toprevent any high frequency oscillations which may occur at the time ofbreak-down of any one of the spark gaps from reaching the supply line 2"and the power supply source.

In this case also, a charging condenser 42" is preferably connected tothe supply line 2", the other side of said condenser being grounded asindicated at 43".

The operation of this form of the invention is substantially the same asdescribed above in connection with Fig. 2, with the exception that allof the impulse condensers and spark gaps are at all times electricallyconnected to the source of electric power. However, by making thecondensers 5a", 5b and 5c of different capacities, or by making thespark gaps 3a", 3b" and 3c" of different lengths, the break-down of therespective gaps will be caused to take place at different timeintervals, due to the difference in time required to charge therespective condensers sufliciently to cause break-down of thecorresponding gaps. The resistances or inductances 34 are preferably ofsuflicient magnitude to prevent disturbance in any one of the impulsecircuits at the time of break-down and discharge in any one of the otherimpulse circuits. If desired, these resistances or inductances may alsobe made of different magnitudes in the respective branch circuits, so asto provide the desired difference in time of discharge in thecorresponding impulse circuits.

It will be seen that, in each of the circuits above-described the hightension electrode means of each treating unit is free from connection tothe source of high potential unidirectional current, other than throughthe spark gap means associated with that particular unit, and since anelectrical connection across the spark gap means is established only atthe time of break-down thereof, the electrical energy is delivered toeach treating unit wholly in the form of the high potential impulses ofsteep wave front and short duration, which occur at the time of suchbreakdown.

I claim:

1. In combination with an apparatus for electrical treatment of fluidscomprising a plurality of electrical treating units, an energizingcircuit comprising a common source of unidirectional high voltage, aplurality of branch circuits leading from said common source to therespective treating units, electrical capacity means connected to saidcircuit, and separate spark gap means connected in each of said branchcircuits for causing sharp unidirectional potential impulses ofextremely short duration to be delivered at different times through therespective spark gap means to the respective treating units. a

2. In combination with an apparatus for electrical treatment of fluidscomprising a plurality of electrical treating units, an energizingcircuit comprising a common source of unidirectional high voltage, aplurality of branch circuits leading from one side of said common sourceto one side of the respective treating units, a separate capacity meansconnected to each of said branch circuits to receive energy from saidcommon source, and a spark gap means connected in each of said branchcircuits between said capacity means and said one side of thecorresponding treating unit so as to deliver unidirectional potentialimpulses of extremely short duration to said treating unit uponbreak-down of said spark gap means, due to the discharge of saidcapacity means across said gap said one side of each of said treatingunits being free from connection to said source other than through thecorresponding spark gap means, and the other side of all of saidtreating units being connected to the other side of said source.

3. In combination with an apparatus for electrical treatment of fluidscomprising a plurality of electrical treating units, an energizingcircuit comprising a common source of high potential unidirectionalcurrent, a plurality of branch circuits leading from said common sourceto the respective treating units, separate capacity means connected toeach of said branch circuits to receive energy from said common source,separate spark gap means connected in each of said branch circuitsbetween the corresponding capacity means and the corresponding treatingunit so as to deliver unidirectional potential impulses of extremelyshort duration to said treating unit upon break-down of said spark gapmeans, by discharge of said capacity means across said spark gap, andmeans included in said energizing circuit for controlling the time ofoperation of the respective spark gap means, so as to cause break-downof the respective spark gap means and delivery of impulses to thecorresponding treating units to occur at different times.

4. In combination with an apparatus for an electrical treatment offluids comprising a plurality of electrical treating units, anenergizing circuit comprising a common source of high potentialunidirectional current, a plurality of branch circuits leading from saidcommon source to the respective treating units, separate capacity meansassociated with each of said branch circuits, and rotary spark gap meansincluded in each of said branch circuits and operable when in oneposition to provide spark gap connectior of the associated capacitymeans to said common source and when in another position to providespark gap connection from said capacity means to the correspondingtreating unit, the rotary spark gap means for the respective treatingunits being angularly offset with respect to one another so as to causesuch spark gap connections to be established at different times in therespective branch circuits.

5. In combination with an apparatus for electrical treatment of fluidscomprising a plurality of electrical treating units, an energizingcircuit comprising a common source of high potential unidirectionalcurrent, a plurality of branch circuits connected to the respectivetreating units, separate capacity means connected to each of said branchcircuits, separate spark ap means connected in each of said branchcircuits between said capacity means and the corresponding treating unitso as to deliver unidirectional potential impulses of extremely shortduration to said treating unit upon break-down of said spark gap means,and switching means connected between said common source and therespective branch circuits and operable to successively establishconnection from said common source to the respective branch circuits.

6. In combination with an apparatus for electrical treatment of fluidscomprising a plurality of electrical treating units, an energizingcircuit comprising a common source of unidirectional high voltage, aplurality of branch circuits leading from said common source to therespective treating units, impedance means in each of said branchcircuits, separate capacity means connected to each of said branchcircuits to receive energy from said common source, separate sparkpacity means, and the length 01' the spark gap means being different inthe respective branch circuits, so as to cause break-down of therespective spark gap means and delivery of impulses to the correspondingtreating units to occur at different times.

CARL HAHN.

